The first group of methods utilizes special beam rotating elements, for example, in the form of prisms in order to spatially turn the beam clusters emitted by the individual emitters by an angle of typically 90° (U.S. Pat. No. 5,168,401 A; EP 0 484 276 A1; U.S. Pat. No. 5,513,201 A). In a second group of arrangements, the output radiation of the laser diodes passes through a system consisting of two highly reflective surfaces that are slightly inclined relative to one another, such that a suitable reconfiguration of the laser diode cluster is achieved at the output of this system (WO 95/15510). The disadvantage of these two groups of arrangements is, in particular, the complexity of the micro-optical elements used, wherein this applies, in particular, to the beam rotation that appears to make it extremely difficult to combine larger numbers of emitters into a laser diode array, as well as the high adjusting expenditure of the entire system and the inability to manufacture systems of this type inexpensively.
Less complicated optical beam transformation systems are disclosed in DE 198 20 154 A1 and DE 196 45 150 A1. DE 198 20 154 A1 describes a device for the optical beam transformation of a beam cluster with an extensive beam cross section, wherein said device comprises optical elements with optically active boundary surfaces that are arranged in the beam path. The deflection of the beam clusters is achieved with a Fourier lens that, as a collimator system simultaneously minimizes the divergence of the whole beam. A downstream deflection element is situated in the rear focal plane of the Fourier lens. In the arrangement according to DE 198 20 154 A1, the radiation emitters need to be arranged in the front focal plane of the Fourier lens and the second angular transformation element needs to be arranged in the rear focal plane of the Fourier lens. This disadvantageously results in a significant overall length of the arrangement due to the distance between the emitters and the deflection element that amounts to at least twice the focal length of the Fourier lens. In addition, the Fourier lens needs to have a large aperture and adequate focusing characteristics, i.e., a long focal length, because the beam clusters of the emitters have a significant divergence upstream of the Fourier lens and extend parallel to the optical axis. Another disadvantage can be seen in the fact that the beam characteristics and the deflection angles of the beam clusters cannot be adjusted independently of one another.